Proposed is the purchase of a multi-mode, multi-channel transmitter to bring new utility to our 9.4T / 65 cm bore NMR system for an increasing number of human and animal studies. In pursuit of higher signal-to-noise, increased spectral resolution, improved parallel imaging speed, and other performance improvements in anatomic, metabolic, and functional imaging , investigators at the University of Minnesota's Center for Magnetic Resonance Research have designed a dozen or more NIH supported projects to take advantage of these 9.4T benefits. Since this highest field system was first proposed and funded, beginning a decade ago, new problems with and new solutions for imaging at this unprecedented field strength have come to light. Among the problems, conventional means of RF excitation of the NMR signal do not work. Due to the 9cm wavelength in brain or muscle tissue at 400 MHz , the RF excitation field generated by conventional, fixed resonators driven by conventional, single channel RF amplifiers, is too non-uniform and too power consumptive for most biomedical applications in larger lab animal or human studies. Solutions to this problem depend on the ability to dynamically control the RF excitation field over a number of degrees of freedom, namely phase, magnitude, time, space, and frequency. By manipulating the RF field over these degrees of freedom (by methods now called B1 shimming, Transmit SENSE, and others yet to be named), RF field characteristics can be "optimized" to select for desired criteria (max SNR, min SAR, homogeneity, etc.) over targeted regions of interest in the anatomy. To achieve this control in practice, a multi-mode, multi-channel RF power transmitter is needed to drive a multi-channel RF coil, hence the item purchase requested. The research projects supporting this proposal, both develop and benefit from these new degrees of freedom in NMR imaging and spectroscopy on the inherently most powerful platform yet available for human research In vivo. PUBLIC HEALTH RELEVANCE: In terms of inherent resolving power and speed, the 9.4T NMR (MRI) system at the University of Minnesota's Center for Magnetic Resonance Research, is the most powerful instrument today for non-invasively imaging living human anatomy, chemistry, and physiology in states of health, disease, and therapeutic intervention. To realize the full potential of this investigational tool however, and to support the increasing number of NIH funded projects using it, a major new up-grade of the radio-frequency transmitter sub-system is needed. The required multi-mode, multi-channel transmitter was actually developed with NIH grant support at the University of Minnesota, and is now commercially available in a safe, high power, robust (non-prototype) form from Communications Power Corporation in Happague, NY.